The invention relates generally to hoist buckets, and more particularly to cylindrical hoist bukets for moving free flowing granular material with cranes and traveling gantries.
Hereto the prior art has taught clamshell hoist buckets comprising two or more scoop elements pivoted together on non-concentric scoop centers that compress scooped material. See U.S. Pat. Nos. to Bricon 4,059,886; Cullings 4,005,895; McCain 3,627,371; Bormiola 3,589,766; Wallers 3,194,329; Chatrenet 2,889,643; Billings 3,627,371; O'Leary 3,187,916; and Shovick 3,807,589. The closest reference is Weber, U.S. Pat. No. 3,606,435 which teaches a bore hole clamshell hoist bucket comprising two quarter spherical scoop elements pivoted concentrically to form an open half spherical bucket.
The invention teaches a cylindrical hoist bucket comprising two nested half cylinders pivoted together at respective closed ends on a common concentric axis for each half cylinder to pivot 90 degrees to completely close around free flowing granular material without compressing said material and allowing escape of dust from said material.